The present invention broadly relates to automatic machine tools and, in particular, concerns a new and improved construction of automatic lathe.
By means of so-called thread chasing or thread cutting operations it is possible to produce at turning machines or lathes of the most different species very accurate threads with high surface. The predominent type of thread chaser mechanisms are assemblies which, for instance, can be attached to a slide or a turret of a lathe or turning machine. The tool --a thread cutting or thread chaser chisel-- is attached to a chaser slide belonging to such assembly and to which there is imparted by means of guide cams repetitive longitudinal and transverse movements.
Particularly in the case of automatic face or front lathes and similar turning machines which possess a compound slide as the tool support the mounting of a thread chaser mechanism --especially the construction of a chaser slide-- is extremely problematic. The chaser slide requires a great deal of space and thus considerably reduces the work space of the machine. Due to the deficiency in space additionally the chaser slides and the associated guides are oftentimes too small and of insufficient robust construction for the high cutting forces which arise during thread chasing.
In the case of automatic face lathes or the like in which the longitudinal and transverse movements of the compound slide and the tools secured thereon are controlled by primary control cams, it would be possible through the use of the latter to simulate a thread chasing operation as part of a work cycle; this has the advantage that there are eliminated the drawbacks associated with a chaser slide. However, there would be only possible very few chaser strokes since for the control thereof it would be necessary to provide a great deal of space at the primary control cams, in other words there would remain only very little space for the control of other turning or lathe operations at the same workpiece during one chucking.